As systems for assisting vehicle drivers, there has been proposed a system that switches on or off a headlight according to the luminance around the vehicle. PTL 1 below describes a vehicle headlight control system that decreases illuminance of the headlight, when the vehicle is to be parked in a specific parking area, such as a home parking area, and when there is a residential house within an illumination range of the headlight of the vehicle. This system uses, as a basis, the image information on nearby residential houses captured by a camera or the information on nearby residential houses in a map database, and a vehicle azimuth detected by an azimuth sensor to determine a positional relationship between the illumination range of the vehicle headlight and the nearby residential houses. When the nearby residential houses are present within the illumination range of the vehicle headlight, this system decreases the illuminance of the headlight.